# 打印城市及其所属国家等信息

def city_belong(city, country):
	"""打印城市及其所属国家"""
	city_belong_country = f"{city.title()}, {country.title()}"
	print(city_belong_country)
	return city_belong_country

def city_country_population(city, country, population):
	"""打印城市及其所属国家"""
	city_country_pop = f"{city.title()}, {country.title()} - population {population}"
	print(city_country_pop)
	return city_country_pop

def city_country_population_final(city, country, population=''):
	"""打印城市及其所属国家和人口数"""
	if population:
		city_country_pop = f"{city.title()}, {country.title()} - population {population}"
		print(city_country_pop)
	else:
		city_country_pop = f"{city.title()}, {country.title()}"
	return city_country_pop
	